205090 has 8 divisors (see below), whose sum is σ = 369180. Its totient is φ = 82032.

The previous prime is 205081. The next prime is 205097. The reversal of 205090 is 90502.

It can be written as a sum of positive squares in 2 ways, for example, as 194481 + 10609 = 441^2 + 103^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (205097) by changing a digit.

205090 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10245 + ... + 10264.

2²⁰⁵⁰⁹⁰ is an apocalyptic number.

205090 is a deficient number, since it is larger than the sum of its proper divisors (164090).

205090 is a wasteful number, since it uses less digits than its factorization.

205090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20516.

The product of its (nonzero) digits is 90, while the sum is 16.

The square root of 205090 is about 452.8686343743. The cubic root of 205090 is about 58.9723129693.

Adding to 205090 its reverse (90502), we get a palindrome (295592).

The spelling of 205090 in words is "two hundred five thousand, ninety".